7. REFRIGERANT R410A
This air conditioner adopts the new refrigerant HFC (R410A) which does not damage the ozone layer.
The working pressure of the new refrigerant R410A is 1.6 times higher than conventional refrigerant (R22). The refrigerating oil is also changed in accordance with change of refrigerant, so be careful that water, dust, and existing refrigerant or refrigerat- ing oil are not entered in the refrigerant cycle of the air conditioner using the new refrigerant during installation work or servicing time.
The next section describes the precautions for air conditioner using the new refrigerant. Conforming to contents of the next section together with the general cautions included in this manual, perform the correct and safe work.
7-1. Safety During Installation/Servicing
As R410A’s pressure is about 1.6 times higher than that of R22, improper installation/servicing may cause a serious trouble. By using tools and materi- als exclusive for R410A, it is necessary to carry out installation/servicing safely while taking the following precautions into consideration.
(1)Never use refrigerant other than R410A in an air conditioner which is designed to operate with R410A.
If other refrigerant than R410A is mixed, pres- sure in the refrigeration cycle becomes abnor- mally high, and it may cause personal injury, etc. by a rupture.
(2)Confirm the used refrigerant name, and use tools and materials exclusive for the refrigerant R410A.
The refrigerant name R410A is indicated on the visible place of the outdoor unit of the air condi- tioner using R410A as refrigerant. To prevent mischarging, the diameter of the service port differs from that of R22.
(3)If a refrigeration gas leakage occurs during installation/servicing, be sure to ventilate fully.
If the refrigerant gas comes into contact with fire, a poisonous gas may occur.
(4)When installing or removing an air conditioner, do not allow air or moisture to remain in the refrigeration cycle. Otherwise, pressure in the refrigeration cycle may become abnormally high so that a rupture or personal injury may be caused.
(5)After completion of installation work, check to make sure that there is no refrigeration gas leakage.
If the refrigerant gas leaks into the room, coming into contact with fire in the
(6)When an air conditioning system charged with a large volume of refrigerant is installed in a small room, it is necessary to exercise care so that, even when refrigerant leaks, its concentration does not exceed the marginal level.
If the refrigerant gas leakage occurs and its concentration exceeds the marginal level, an oxygen starvation accident may result.
(7)Be sure to carry out installation or removal according to the installation manual.
Improper installation may cause refrigeration trouble, water leakage, electric shock, fire, etc.
(8)Unauthorized modifications to the air conditioner may be dangerous. If a breakdown occurs please call a qualified air conditioner technician or electrician.
Improper repair’s may result in water leakage, electric shock and fire, etc.
7-2. Refrigerant Piping Installation
7-2-1. Piping Materials and Joints Used
For the refrigerant piping installation, copper pipes and joints are mainly used. Copper pipes and joints suitable for the refrigerant must be chosen and installed. Furthermore, it is necessary to use clean copper pipes and joints whose interior surfaces are less affected by contaminants.
(1)Copper Pipes
It is necessary to use seamless copper pipes which are made of either copper or copper alloy and it is desirable that the amount of residual oil is less than 40 mg/10 m. Do not use copper pipes having a collapsed, deformed or discol- ored portion (especially on the interior surface). Otherwise, the expansion valve or capillary tube may become blocked with contaminants.
As an air conditioner using R410A incurs pressure higher than when using R22, it is necessary to choose adequate materials.
Thicknesses of copper pipes used with R410A are as shown in Table
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